De-swaging technique for head gimbal assembly

ABSTRACT

In a magnetic head carrying device a method and apparatus for removing a magnetic head carrying arm from a support arm wherein ball stake mounting is used to affix the magnetic head carrying arm to the support arm. Tool receiving holes are provided in the magnetic head carrying arm, in a mounting plate, and in the support arm. Raised portions of a first tool may be inserted into the tool receiving holes of the magnetic head carrying arm and of the mounting plate. Raised portions of a second tool may be inserted into the tool receiving hole of the support arm. As the first and second tools are forced together, the ball stake mount is disassembled.

BACKGROUND OF THE INVENTION

The present invention relates to the arm used to carry a magnetic headin a magnetic disk drive unit. In particular, the invention relates to amethod of removing a ball stake (or swage) mounted magnetic head fromthe support arm.

There has been a continual drive to increase the storage density inmagnetic disk drive units. This has been achieved in part by stackingmagnetic disks in a "pack" all carried within the same disk drive unit.Each side of each disk has its own associated magnetic head used forreading and writing information thereon. Each magnetic head has its ownassociated support arm which positions the head above the disk surface.By moving the arm, the magnetic head is moved between tracks on the disksurface. A servomotor is connected to the opposite end of the supportarm. The magnetic head is moved between tracks by activating theservomotor whereby the support arm pivots and the magnetic head at theopposite tip of the arm is swung between adjacent tracks on the disksurface. A linear actuator may alternatively be used to move a magnetichead. A linear actuator moves the head inward or outward on the diskalong a straight line.

To further increase space savings in the disk drive unit, a singleservomotor typically controls all of the support arms and theirassociated magnetic heads. Thus, all of the support arms are connectedtogether and pivot about the same pivot point. This configuration isidentified as an "E-block" (which refers to the shape formed by theadjacent arms and the servomotor/pivot assembly).

Each magnetic head is connected to the support arm using a mountingmethod known as "ball staking" or "swaging." In ball staking two pieces,a hole in one piece is aligned with a hollow tube which extends from asecond piece. A rounded shape (the "ball") is forced through the hollowtube which causes the tube metal to expand and lock the two piecestogether.

A problem associated with past ball stake mount designs is that therewas no economical method to remove a single defective magnetic head fromthe assembly. Once ball stake mounted, the support structure was verydifficult to disassemble and was easily damaged. Thus, the entireE-block assembly typically had to be replaced if a single magnetic headmalfunctioned.

One attempt to overcome the problems associated with past ball stakemount designs was disclosed in Toensing, U.S. Pat. No. 5,012,367 whichhas been assigned to Seagate Technology, Inc., the assignee of thepresent application. Toensing disclosed a removable ball staked headgimbal assembly as well as a method and apparatus of removing theassembly. In the assembly disclosed in Toensing, a bevel was providedbetween the ball staked support arm and magnetic head carrying arm. Aremoval tool is then inserted into the bevel so that the ball stakedpieces are pried apart. The bevel is preferably provided by a mountingplate which is mounted to one of the arms. Ball staking occurs throughthe method described above.

In some instances, the deswaging operation causes the support arm to bebent during the removal process. If a single support arm of an E-blockassembly is bent, the entire E-block assembly must be scrapped,increasing both the labor and the material costs of repair. Removal ofthe ball staked assembly may also result in damage to the magnetic headsupporting arm. Often times, this makes it impossible to perform afailure analysis on the defective magnetic head assembly.

SUMMARY OF THE INVENTION

The present invention provides a method for removing a single ballstaked magnetic head from its associated support arm. Using the presentinvention when a single magnetic head in an E-block assemblymalfunctions, it is only necessary to replace that magnetic head,without discarding the entire E-block assembly.

In the present invention, a magnetic transducer support is provided, thesupport comprises a first arm which carries a magnetic transducer head,a mounting plate which is joined to the first arm, and a second arm. Thefirst arm includes a first hole which creates a first passageway throughthe first arm. Tool receiving holes in the first arm also createpassageways therethrough for receiving a first disassembly tool. Asecond arm includes a hole, aligned with the first hole, the hole beingcapable of receiving a second disassembly tool. A mounting plate, joinedto the first arm, includes a tubular member aligned with the first holeof the first arm and with the hole of the second arm. The tubular memberextends into the hole of the second arm for ball staking the mountingplate to the second arm. The tubular member has a diameter smaller thanthe diameter of the hole in the second arm so that the seconddisassembly tool may not be inserted into the mounting plate. Themounting plate also has tool receiving holes aligned with the toolreceiving holes of the first arm for receiving the first disassemblytool.

To remove the ball staked assembly, the first disassembly tool isinserted into the aligned tool receiving holes of the first arm andmounting plate. A second disassembly tool is inserted into the hole ofthe second arm. The first and second disassembly tools are forced towardeach other so that the first disassembly tool applies force on thesecond arm and so that the second disassembly tool applies force on thejoined first arm and mounting plate, pushing the first and second armsapart. The present invention offers significant cost advantages over theprior art because it results in reduced labor and material costs byreducing the number of E-block assemblies that must be discarded as aresult of damage during removal of a single malfunctioning magnetichead.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a disk pack and its associated E-block assembly.

FIG. 2 is a top view of a magnetic disk and magnetic head arm.

FIG. 3 is a top view of a magnetic head arm.

FIG. 4 is a side view of a magnetic head arm, a magnetic head assemblyand a magnetic disk surface.

FIG. 5 is a side view of the ball staked magnetic head arm of thepresent invention.

FIG. 6 is a side view of an alternative embodiment of the ball stakedmagnetic head arm of the present invention.

FIG. 7 is a perspective view of the ball staked magnetic head arm of thepresent invention.

FIG. 8 is a perspective view of a tool used to remove the ball stakedmount.

FIG. 9 is a perspective view showing the relationship between theremoval tool and the ball staked mount.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A disk drive assembly 10 is shown in FIG. 1 comprising a disk pack 12and E-block assembly 14. Disk pack 12 comprises disks 16 stacked on adrive spindle 18. E-block assembly 14 comprises a servo spindle 20 and aplurality of support arms 22. Each support arm 22 carries one or twoflexure arms 24. Each flexure arm 24 carries a magnetic head assembly26. Each flexure arm 24 is mounted to its corresponding support arm 22by ball stake mount 28. The particular method of mounting ball stakemount 28 is explained below in more detail.

FIG. 2 shows a top view of disk drive assembly 10 of FIG. 1. Servospindle 20 rotates around a pivot axis 30. As servo spindle 20 rotates,magnetic head assembly 26 mounted at the tip of flexure arm 24 swingsthrough arc 32. As disk 16 rotates beneath magnetic head 26, thispivoting motion allows magnetic head assembly 26 to change trackpositions on disk 16. As shown in FIG. 1, as drive spindle 18 rotatesall magnetic head assemblies 26 move in unison.

In FIGS. 3 and 4, a more detailed diagram of flexure arm 24 is shown.Flexure arm 24 is spring loaded, whereby magnetic head assembly 26 isheld in close proximity to disk 16. As disk 16 rotates at high speedabout drive spindle 18, the aerodynamic properties of magnetic headassembly 26 cause assembly 26 to "fly" above the surface of disk 16. Theflying height of magnetic head assembly 26 above disk 16 is a functionof the speed of rotation of disk 16, the aerodynamic lift of magnetichead assembly 26 and the spring tension in flexure arm 24.

FIG. 5 shows the removable ball stake mount 28 of the present invention.Ball stake mount 28 connects support arm 22 and flexure arm 24. FIG. 5shows a mounting plate 60 with a tubular member 62 which extends throughhole 63 in flexure arm 24 and hole 42 in support arm 22. Mounting plate60 includes tool receiving holes 64 which create a passageway throughmounting plate 60. Similarly, flexure arm 24 includes tool receivingholes 66 which create a passageway through flexure arm 24. Toolreceiving holes 64 and 66 are aligned so that a first disassembly tool(shown in FIGS. 11 and 12) may be inserted into the passageway createdby tool receiving holes 64 and 66. During manufacture, mounting plate 60is bonded to flexure arm 24 using, for example, a laser weldingprocedure. Ball staked mount 28 is ball staked in the method asdescribed above by forcing an object with a diameter larger than thediameter of tubular member 62 through tubular member 62, hole 63 inflexure arm 24, and hole 42 in support arm 22. As will be discussed,hole 42 in support arm 22 and tool receiving holes 64 and 66 in mountingplate 60 and flexure arm 24 provide the means for separating support arm22 from flexure arm 24 following ball staking.

FIG. 6 shows an alternative embodiment of the removable ball stake mountshown in FIG. 5. As is the case with ball stake mount 28, ball stakemount 70 connects support arm 22 to flexure arm 24. Flexure arm 24 stillincludes hole 63 and tool receiving holes 66. Mounting plate 60 stillincludes tubular member 62 and tool receiving holes 64. Tool receivingholes 64 of mounting plate 60 are aligned with tool receiving holes 66of flexure arm 24. However, in the embodiment of FIG. 6, mounting plate60 is sandwiched between support arm 22 and flexure arm 24, with tubularmember 48 extending through hole 42 of support arm 22.

FIG. 7 shows another view of the ball stake mount 28 shown in FIG. 5. InFIG. 7, support arm 22 is shown ball stake mounted to flexure arm 24 andmounting plate 60. Also shown in FIG. 7 are four tool receiving holes 64in mounting plate 60 aligned with four tool receiving holes 66 inflexure arm 24. At the bottom of each aligned pair of tool receivingholes 64 and 66 is a portion of support arm 22, which prevents adisassembly tool (shown in FIGS. 8 and 9) from passing through ballstake mount assembly 28. Also shown is hole 42 of support arm 22 whichhas a larger diameter than tubular member 62 so that a seconddisassembly tool (shown in FIGS. 8 and 9), which is inserted into hole42, will not pass through ball stake mount assembly 28.

FIG. 8 shows a first disassembly tool 74 with cylindrical raisedportions 76 and a second disassembly tool 78 with cylindrical raisedportion 80. Disassembly tools 74 and 78 may be used in conjunction withball stake mount 28 and 70 of the present invention to separate supportarm 22 from flexure arm 24 following ball staking.

FIG. 9 illustrates how disassembly tools 74 and 78 are used with ballstake mount 28 to separate flexure arm 24 from support arm 22.Disassembly tool 74 is pushed into ball stake mount 28 so thatcylindrical raised portions 76 pass through tool receiving holes 64 ofmounting plate 60 and tool receiving holes 66 of flexure arm 24. Asdisassembly tool 74 is pushed toward ball stake mount 28, the surface ofraised portions 76 come into direct contact with portions of support arm22. Similarly, disassembly tool 78 is pushed toward ball stake mount 28so that cylindrical raised portion 80 passes through hole 42 of supportarm 22 and comes into direct contact with portions of tubular member 62.As disassembly tools 74 and 78 are brought together, the pressureexerted by raised cylindrical portion 80 on tubular member 62 pushesflexure arm 24 and mounting plate 60 away from support arm 22. Likewise,the pressure exerted by raised cylindrical portions 76 on support arm 22pushes support arm 22 away from flexure arm 24 and mounting plate 60. Inthis manner, disassembly tools 74 and 78 may be used to separate flexurearm 24 and support arm 22 while causing less stress on ball stake mount28. Therefore, the likelihood of damaging either flexure arm 24 orsupport arm 22 is decreased.

Holes 64 in mounting plate 60 and holes 66 in flexure arm 24 allow thedisassembly force to be more evenly spread over support arm 22. Thisreduces the torque applied to arm 22, thereby reducing any deformationof arm 22 during deswaging which might damage arm 22.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in the form and detail without departing from thespirit and scope of the invention. For example, the raised portions ofthe disassembly tools may be formed in any useful shape. Additionally,the number and shape of tool receiving holes in the ball stake mount maybe changed.

What is claimed is:
 1. An apparatus in a magnetic transducer support forconnecting a magnetic transducer carrying arm to a support arm, theapparatus comprising:a ball stake connection for mounting the supportarm to the transducer carrying arm, the ball stake connection comprisinga first hole defined in the support arm and creating a passagewaythrough the support arm, a second hole defined in the transducercarrying arm substantially aligned with the first hole and creating apassageway through the transducer carrying arm, and a tubular memberwhich extends through the first and second holes for connecting thetransducer carrying arm to the support arm; and a plurality of toolinsertion holes defined in one of the transducer carrying arm and thesupport arm for receiving a first tool therethrough, the tool insertionholes being arranged in a pattern in the one arm around the respectivefirst or second hole, the other of the support arm and the transducercarrying arm having a surface exposed to the tool insertion holes,wherein the first tool extends through the tool insertion holes to applya force to the surface on the other of the support arm and thetransducer carrying arm to disconnect the tubular member from at leastone of the transducer carrying arm and the support arm therebydisengaging the ball stake connector.
 2. The apparatus of claim 1,wherein the tool insertion holes are defined in the transducer carryingarm so that the first tool applies force to the surface of the supportarm and the first hole defined in the support arm is adapated forreceiving a second tool therethrough, wherein the second tool applies aforce to the transducer carrying arm while the first tool applies aforce to the surface of the support arm thereby disengaging the ballstake connection.
 3. The apparatus of claim 1, wherein the toolinsertion holes defined in the one of the transducer carrying arm andthe support arm are so disposed and arranged relative to one anotherthat the ball stake connection is disengaged without substantiallybending the support arm.
 4. The apparatus of claim 1, wherein the toolinsertion holes defined in the one of the transducer carrying arm andthe support arm are so disposed and arranged relative to one anotherthat the ball stake connection is disengaged without substantiallybending the transducer carrying arm.
 5. A magnetic transducer supporthaving a transducer carrying arm and a support arm and a swageconnection mounting the transducer carrying arm to the support arm, themagnetic transducer support comprising:a plurality of first toolinsertion holes defined in one of the transducer carrying arm and thesupport arm for receiving a first tool, the tool insertion holes beingarranged in a pattern in the one arm around the swage connection theother of the support arm and the transducer carrying arm having asurface exposed to the first tool insertion holes wherein the first toolapplies a force through the first tool insertion holes and against thesurface on the other of the support arm and the transducer carrying armto disengage the swage connection thereby separating the transducercarrying arm and the support arm.
 6. The magnetic transducer support ofclaim 5 and further comprising:a second tool insertion hole defined inthe other of the support arm and the transducer carrying arm forreceiving a second tool, wherein the second tool applies a force throughthe second tool insertion hole and against a surface of the one of thetransducer carrying arm and the support arm thereby separating thetransducer carrying arm and the support arm.
 7. The magnetic transducersupport of claim 5 and further comprising:a mounting plate for swagemounting the transducer carrying arm to the support arm; and a pluralityof third tool insertion holes defined in the mounting plate and alignedwith the plurality of first tool insertion holes for receiving the firsttool, wherein the first tool applies a force through the first and thirdtool insertion holes and against the other of the support arm and thetransducer carrying arm thereby separating the transducer carrying armand the support arm.
 8. An apparatus in a magnetic transducer supportfor connecting a transducer carrying arm to a support arm with a ballstake connector, the apparatus comprising:a first hole defined in thesupport arm for receiving the ball stake connector for connecting thetransducer carrying arm to the support arm; a second hole defined in thetransducer carrying arm for receiving the ball stake connector forconnecting the transducer carrying arm to the support arm, the secondhole being aligned with the first hole; and a plurality of toolinsertion holes defined in one of the transducer carrying arm and thesupport arm for receiving a first tool therethrough, the tool insertionholes being arranged in a pattern in the one arm around the respectivefirst or second hole the other of the support arm and the transducercarrying arm having a surface exposed to the tool insertion holes,wherein the first tool applies a force through the tool insertion holesand against the surface on the other of the support arm and thetransducer carrying arm to disconnect the ball stake connector from atleast one of the transducer carrying arm and the support arm therebydisconnecting the transducer carrying arm and the support arm.
 9. Theapparatus of claim 8, wherein the tool insertion holes defined in theone of the transducer carrying arm and the support arm are so disposedand arranged relative to the first and second holes that the transducercarrying arm and the support arm are disconnected without substantiallybending the support arm.
 10. The apparatus of claim 8, wherein the toolinsertion holes defined in the one of the transducer carrying arm andthe support arm are so disposed and arranged relative to the first andsecond holes that the transducer carrying arm and the support arm aredisconnected without substantially bending the transducer carrying arm.